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Titolo:
A novel approach towards intermolecular stabilization of para-quinone methides. First complexation of the elusive, simplest quinone methide, 4-methylene-2,5-cyclohexadien-1-one
Autore:
Rabin, O; Vigalok, A; Milstein, D;
Indirizzi:
Weizmann Inst Sci, Dept Organ Chem, IL-76100 Rehovot, Israel Weizmann InstSci Rehovot Israel IL-76100 Chem, IL-76100 Rehovot, Israel
Titolo Testata:
CHEMISTRY-A EUROPEAN JOURNAL
fascicolo: 3, volume: 6, anno: 2000,
pagine: 454 - 462
SICI:
0947-6539(20000204)6:3<454:ANATIS>2.0.ZU;2-#
Fonte:
ISI
Lingua:
ENG
Soggetto:
BUTYLATED HYDROXYTOLUENE HYDROPEROXIDE; CRYSTAL-STRUCTURE; REACTIVITY; PROTEINS; BHT; ALKYLATION; PALLADIUM; 2,6-DI-TERT-BUTYL-4-METHYLPHENOL; PRECURSORS; GENERATION;
Keywords:
ligand exchange reactions; palladium; P ligands; quinone methides; synthesis design;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
53
Recensione:
Indirizzi per estratti:
Indirizzo: Milstein, D Weizmann Inst Sci, Dept Organ Chem, IL-76100 Rehovot, Israel Weizmann Inst Sci Rehovot Israel IL-76100 00 Rehovot, Israel
Citazione:
O. Rabin et al., "A novel approach towards intermolecular stabilization of para-quinone methides. First complexation of the elusive, simplest quinone methide, 4-methylene-2,5-cyclohexadien-1-one", CHEM-EUR J, 6(3), 2000, pp. 454-462

Abstract

A novel approach towards the intermolecular stabilization of "simple" (i.e. methylene-unsubstituted) p-quinone methides (QMs) by their coordination to a transition-metal center is described. 4-Bromomethyl phenols, protected by a silyl group, were employed as the QM precursors and cis-chelating diphosphine Pd-0 complexes were chosen as the metal precursors, since they havestrong back-bonding interactions with the electron-poor QM moiety. Removalof the silyl protecting-group from the corresponding [LPd(benzyl)Br] complex (L=bisphosphine) with fluoride results in the spontaneous rearrangement of the unobserved zwitterionic Pd-II complex into the QM-Pd-0 complex. The feasibility of this approach was demonstrated in the synthesis of the structurally characterized Pd-0 complex of BHT-QM (Le), a biologically relevant metabolite of 2,6-di-tert-butyl-p-cresol, and the synthesis of the complex of 4-methylene-2,5-cyclohexadien-1-one (11), the simplest, and so far unobserved QM molecule. These complexes exhibit a remarkable thermal stability and do not react with alcohol or water. In both cases, the use of an appropriate incoming ligand allowed the release of the coordinated QM into the reaction media in which it was effectively trapped by added nucleophiles.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 21/09/20 alle ore 06:19:18